Eating healthfully with sight in mind

Sep 28, 2007

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Two common vision problems that come with aging are cataracts and age-related macular degeneration, or ARMD. Cataracts are particularly common in people over the age 75 and macular degeneration is the leading cause of blindness in older adults.

Macular degeneration develops as the macula, the part of the eye that turns light into color images in your brain, becomes damaged and blurs your central vision.

Some risk factors for ARMD, including family history, older age, and light-colored eyes, skin and hair, can't be controlled. Luckily, researchers have identified a number of other factors that can help delay the onset of macular degeneration. These include not smoking; limiting your exposure to sun; wearing protective eyewear; eating a healthful diet that includes plenty of fruits and vegetables high in vitamin C, vitamin E, lutein and zeaxanthin; keeping total and trans fats low; and increasing consumption of foods high in Omega-3 fatty acids.

You've probably heard several of these recommendations before, but why lutein and zeaxanthin? These are pigments found in concentrated amounts in the retina. They help protect the eyes by filtering out blue light, the most damaging portion of the UV spectrum. They also act as antioxidants, scavenging free radicals and protecting the eye against damage caused by sunlight and lipid oxidation.

Lutein and zeaxanthin are found in a variety of foods, particularly winter squash, corn, peas and dark green leafy vegetables like kale, spinach, broccoli and collard greens. They are responsible for the yellow color of corn and winter squash and help make dark green, leafy vegetables green. They're also found in egg yolks.

Several studies in recent years have found a connection between consumption of foods rich in lutein and zeaxanthin and reduced risk of developing age-related cataracts and macular degeneration. For example, in a study completed at Harvard University, those who ate greens and other lutein- and zeaxanthin-rich foods two to four times a week were half as likely to end up with macular degeneration than people who ate them less than once a month. In another study, eating a least three servings weekly of dark green vegetables was protective against cataracts. Two other antioxidants, vitamins C and E, also have been associated with reducing the risk of age-related cataracts and macular degeneration. In most cases, scientists believe these antioxidant nutrients provide protection because of their collective, not solo, action, which argues for getting them in balance through foods, not supplements.

Eating too much fat, or the wrong types of fat, also seems to be a risk factor in increasing progression of macular degeneration. How? By promoting the buildup of plaque in the blood vessels of the eyes, similar to what can happen in the coronary arteries. In a five-year Harvard University follow-up study of persons aged 60 and over with signs of age-related macular degeneration in at least one eye, those who ate the least total fat, least trans fat, least animal fat and most nuts and fish had the lowest progression of the disease.

What if you've avoided dark green and yellow vegetables and loaded up on high-fat meat all your life? Is it too late to play catch up? Cataracts and age-related macular degeneration do occur over time. Many researchers believe that diets high in antioxidant nutrients and low in total and trans fats not only can help prevent eye diseases, but may also help prevent further deterioration of existing conditions.